[NET] sysctl: make the sys.net.core sysctls per-namespace
Making them per-namespace is required for the following
two reasons:
First, some ctl values have a per-namespace meaning.
Second, making them writable from the sub-namespace
is an isolation hole.
So I introduce the pernet operations to create these
tables. For init_net I use the existing statically
declared tables, for sub-namespace they are duplicated
and the write bits are removed from the mode.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index f97b2a4..d593611 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -37,6 +37,9 @@
struct sock *rtnl; /* rtnetlink socket */
+ /* core sysctls */
+ struct ctl_table_header *sysctl_core_hdr;
+
/* List of all packet sockets. */
rwlock_t packet_sklist_lock;
struct hlist_head packet_sklist;
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index e322713..57a7ead 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -151,18 +151,58 @@
{ .ctl_name = 0 }
};
-static __initdata struct ctl_path net_core_path[] = {
+static __net_initdata struct ctl_path net_core_path[] = {
{ .procname = "net", .ctl_name = CTL_NET, },
{ .procname = "core", .ctl_name = NET_CORE, },
{ },
};
+static __net_init int sysctl_core_net_init(struct net *net)
+{
+ struct ctl_table *tbl, *tmp;
+
+ tbl = net_core_table;
+ if (net != &init_net) {
+ tbl = kmemdup(tbl, sizeof(net_core_table), GFP_KERNEL);
+ if (tbl == NULL)
+ goto err_dup;
+
+ for (tmp = tbl; tmp->procname; tmp++)
+ tmp->mode &= ~0222;
+ }
+
+ net->sysctl_core_hdr = register_net_sysctl_table(net,
+ net_core_path, tbl);
+ if (net->sysctl_core_hdr == NULL)
+ goto err_reg;
+
+ return 0;
+
+err_reg:
+ if (tbl != net_core_table)
+ kfree(tbl);
+err_dup:
+ return -ENOMEM;
+}
+
+static __net_exit void sysctl_core_net_exit(struct net *net)
+{
+ struct ctl_table *tbl;
+
+ tbl = net->sysctl_core_hdr->ctl_table_arg;
+ unregister_net_sysctl_table(net->sysctl_core_hdr);
+ BUG_ON(tbl == net_core_table);
+ kfree(tbl);
+}
+
+static __net_initdata struct pernet_operations sysctl_core_ops = {
+ .init = sysctl_core_net_init,
+ .exit = sysctl_core_net_exit,
+};
+
static __init int sysctl_core_init(void)
{
- struct ctl_table_header *hdr;
-
- hdr = register_sysctl_paths(net_core_path, net_core_table);
- return hdr == NULL ? -ENOMEM : 0;
+ return register_pernet_subsys(&sysctl_core_ops);
}
__initcall(sysctl_core_init);
